The floor at the hospital on which this has been happening has been evacuated, but Tomball police say the hospital has not been shut down or put on lockdown.
Tomball police believe the suspect is armed, but has not made any demands. They also say there are no employees being held hostage.
Negotiations with the suspect are underway.
Earlier the Harris County Sheriff's Office reported the suspect is the father of a patient there.
Tomball police, the Texas Rangers, Harris County Precinct 4 and the Harris County Sheriff's Office are all on the scene.
Keeping all of those in Tomball in my thoughts and prayers.— Michael McCaul (@RepMcCaul) January 11, 2015